It’s 40 years since the first UN Conference on the Human Environment was held in Stockholm, Sweden, in June 1972, which led to the founding of the UN Environment Programme (UNEP). I was too young to remember anything of that event. But what happened exactly 20 years later is unforgettable.

World leaders – including Lankan Prime Minister D B Wijetunga – had converged to Rio de Janeiro, Brazil, for the Earth Summit. As they debated the fate of the planet, Greater Colombo received the heaviest rainfall in living memory: 492mm, or more than one-eighth of its annual rainfall, all on a single night.

World Environment Day 1992 dawned with many areas in and around Colombo under water. That flash flood cut across all class divides: the city’s best residential, diplomatic and business areas were united with shanties in their misery.

The Japanese-built Parliamentary complex in Kotte – less than a decade old at the time – was also partly submerged, causing extensive damage. A nation couldn’t receive a more rude awakening about the urban environmental nightmare it had created…

That week, I had my first direct experience of a disaster: close to four feet of water came inside my Rajagiriya home, and stayed on for three days and nights. Yet I was among the luckier ones – at least I had an upper floor to evacuate.

The blame game started even before the waters receded. Flood victims accused irresponsible local government bodies, greedy property developers and incompetent town planners. There were persistent demands ‘to know who should be held responsible for the floods’.

As A T G A Wickramasuriya, an irrigation engineer with decades of experience, pointed out shortly afterwards, “The floods in Colombo and suburbs was the culmination of a process that was slowly developing due to short-sighted actions taken not only by private individuals but also by government agencies.”

I joined the debate suggesting that all residents in and around Colombo — many of who were narrowly and selfishly focused on their own neck of the woods — shared the blame. We’d either corrupted a corruptible system, or had simply looked away when expediency replaced the due process. As such, I argued, “We drowned in our own apathy and indifference”.

The official response to urban flooding came in October 1993, when the Greater Colombo Flood Control and Environmental Improvement Project was launched. The Japanese assisted project rehabilitated canals, relocated some living on canal banks and set aside a few marshlands for flood retention. These measures probably prevented a recurrence of 1992 – at least for a while.

But protecting Greater Colombo from floods is not easy. It lies almost at sea level and some areas are, in fact, slightly below. Historically a port city, Colombo and suburbs are connected by a network of man-made canals built by the Dutch and expanded by the British. Many of these filled up during the twentieth century from poor maintenance and indiscriminate waste dumping.

Parts of Colombo have underground pipelines to flush out rainwater, but these too fell into disrepair. To make matters worse, natural marshlands were ‘reclaimed’ for roads and buildings – both private and public.

For all these reasons, Colombo’s low-lying areas and some main streets get flooded even with half an hour of heavy showers. The rain water simply has nowhere to go in a hurry.

When the 1992 June floods happened, some town planners and engineers claimed that the rainfall anomaly was a once in 100 year event that no one could design for. Perhaps. But as accelerated climate change kicks in, extreme weather events are becoming more frequent and intense.

So just 18 years later, we had a repeat performance. In mid November 2010, another extra heavy dose of rain in a single night flooded many areas in and around Colombo. As I sat knee-deep inside my flooded office in Nugegoda, I had a strong sense of Déjà vu…

Sri Lankan Parliament flooded after torrential rains in mid-November 2010. The complex, built on a marshland, was completely marooned.

Thousands of affected people groaned loudly, but we weren’t really surprised. Flooding is now almost an annual routine. In a particularly bad year, Parliament also goes under water.

Part of the project’s USD 223 million (approx. LKR 29.5 billion) cost is provided by the World Bank as a loan. Let’s hope the project’s implementers – Ministry of Defence and Urban Development – will take note of the Bank’s broad approach to flood management in cities.

A new World Bank guide launched in April this year warns that urban flooding is “becoming more dangerous and more costly to manage because of the sheer size of the population exposed within urban settlements.”

It isn’t just the megacities that face these challenges. In fact, by 2030 the majority of urban dwellers will live in cities of less than one million people “where urban infrastructure and institutions are least able to cope,” the report cautions. (Colombo city’s population is around 650,000.)

Cover of World Bank Report on Cities and Flooding, 2012

While careful planning and sustained investments are necessary, money and technology alone cannot fix this problem.

It is impossible to completely eliminate flood risk even in countries where disaster risk management is well-funded and understood, says World Bank expert Abhas K Jha, one of the new report’s lead authors.

And although flooding cannot be avoided totally, “we need to design systems that fail gracefully” and to focus on early warning systems, reducing social vulnerability and resettlement of communities most at risk.

He adds: “Policymakers overestimate the value of concrete. Continuous communication is critical as we suffer from ‘half-life memory’ when it comes to disasters. We need to worry about people and assets in harm’s way for the foreseeable future.”

Disaster management experts say disasters normally stay in living memory for about 25 years, but the larger lessons can be easily forgotten. Institutional memories in government agencies tend to be short. Helpfully, the new report lists 12 key principles for integrated urban flood risk management

Water flows according to the laws of physics – and not the whims of politicians or officials. The big challenge for coastal and monsoonal Colombo is to find the right balance between rainwater, economic interests and the public welfare.

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About Nalaka Gunawardene

A science writer by training, I've worked as a journalist and communication specialist across Asia for 25+ years. During this time, I have variously been a news reporter, feature writer, radio presenter, TV quizmaster, documentary film producer, foreign correspondent and journalist trainer. I continue to juggle some of these roles, while also blogging and tweeting and column writing.
There's NOTHING OFFICIAL about this blog. In fact, there's NOTHING OFFICIAL about me! I've always stayed well clear of ALL centres of power and authority.

3 Responses to When Worlds Collide #18: Living with Floods in Colombo: Between rain and the sea

The flood of June 1992 which had been predicted as early as 1981 and not taken seriously should serve as a good starting point of view of flood protection as well as expose the complacent attitudes of own officialdom. This flood was popularly known as a new flood gate constructed by SLLRDC at Nagalagam Street Flood Control Unit of the Irrigation Department, a gate constructed during a failed attempt to clean Beira Lake under another project called MEIP with US $87 million aid from World Bank, which could not opened on time.

If I am not wrong, after 1992 floods, GoSL, design the Greater Colombo Flood Control and Environment Improvement Project with help of foreign consultants. Implementation was in three phases commencing from 1994. I phase (8,000 Million;) II phase (5,800 million): III Phase (5,500 Million). This amount doesnot include all other canal improvements etc. All these projects were completed before 2004. The funds were provided through JBIC.

After 2010/2011 Floods, even though the rainfall(440.2mm on 10th Novemebr 2010) was comparatively lesser than the 1992 rainfall (493.7mm on 4th June 1992), Colombo was still inundated. The economical loss was much much greater than the 1992 loss. Now the government launch the Metro Colombo Urban Developmetn Project (MCUDP) funded by World Bank (29.5 Billion).

Where we have gone wrong??? Is it a spatial planning porblem or lack of expertise. Or too much dependent or technical models?

Flood control systems are designed based on an assessment of risk. The current system is designed for a 50 year return period daily rainfall – which from the statistical analysis of the 100 odd years of data available was about 280 mm. Therefore it is not surprising that the system failed – i.e. there was a flood – when there was 440 mm of rain. Unfortunately the public is not informed of this fact!

If we were richer we would choose a higher return period – like the Dutch, who also have much more to lose. There they used return periods of up to 1000 years for critical structures and have been talking about going further after Hurricane Katrina.

Both the 1992 and 2010 rainfalls are identified as “outliers” – i.e. not normally part of a 100 year record – based on standard statistical analysis. The problem is that the assumptions made in the standard analysis may not be correct. This issue is not unique to Sri Lanka – and more sophisticated methods have been developed that people are trying to use here.

The engineering issue is whether it is possible to design for 400 mm! In the long term the solution is obvious – move to higher ground – and we are lucky that we have plenty of it. This is precisely the logic of the Metropolitan Region Structure Plan – which was approved by the Cabinet in the late 1990s – that envisaged shifting new development to the high ground on the Biyagama-Kaduwela-Homagama belt. It is no coincidence that the Outer Circular Highway takes this route.

By the way – even though I was abroad at the time – it seems extremely unlikely that not being able to open the gate at Nagalagam street was the cause – or even a major contribution – to the 1992 flood.